1. Field of the Invention
The present invention is directed to a coil spring guide with a deflectable tip such as are used in connection with the insertion of a catheter into a vessel of a body. Such coil spring guides are often referred to as angiographic guide wires.
2. Description of the Prior Art
Heretofore coil spring guides or guide wires have been widely used for facilitating the insertion of a catheter into a vessel. In some applications, the coil spring guide with a rounded tip is inserted into a vessel and then the catheter is slipped about the coil spring guide until it is in place and then the guide is retracted from the vessel. In another application, the coil spring guide is first inserted into the catheter tubing with the tip of the guide extending beyond the distal end of the catheter tubing. Then, this assembly is inserted into a vessel with the rounded tip of the coil spring guide facilitating movemement of the guide and catheter tubing into the vessel without puncturing the vessel. Then, once in place, the coil spring guide is retracted leaving the catheter in the vessel.
It is desirable in using such coil spring guides to provide some means for deflecting the tip of the guide to facilitate movement of the guide around or through a curved path in the vessel.
Heretofore there have been a number of proposals for different tip constructions which will provide a deflectable tip in a coil spring guide or guide wire.
Examples of previously proposed coil spring guides including guides with a particular tip construction to facilitate deflecting of the tip are disclosed in the following U.S. patents:
______________________________________ U.S. PAT. NO. PATENTEE ______________________________________ 3,452,740 Muller 3,452,742 Muller 3,521,620 Cook 3,528,406 Jeckel et al. 3,547,103 Cook 3,841,308 Tate 3,973,556 Fleischhacker et al. ______________________________________
The Muller U.S. Pat. No. 3,452,740 discloses an unsheathed coil spring guide manipulator having a core wire with an extension of the core wire extending to a cap or plug at the distal end of a spring coil. The turns of the coil on one side of the spring guide have the side edges of the coils cut away so as to provide a greater space between the respective turns on the side of the spring coil. As a result, pulling of the core wire rearwardly will cause bending of the core wire extension as the coil turns with the sides cut away are compressed against one another. In this way, the tip is caused to deflect.
The Muller U.S. Pat. No. 3,452,742 discloses an unsheated curvable spring guide having the same tip construction as the coil spring in the Muller U.S. Pat. No. 3,452,740 to facilitate deflection of the tip.
The Cook U.S. Pat. No. 3,521,620 discloses a coil spring guide with a bendable tip. The coil spring guide is unsheathed and has a tip member at the distal end of the spring coil. The turns of the coil in the distal end portion of the coil are spaced apart from each other. Two wires are situated within the lumen or cylindrical envelope formed by the coil spring guide and extend to the tip member on diametrically opposite sides of the cylindrical envelope so that one wire is fixed to one lateral edge of the tip member and the other wire is fixed to the opposite lateral edge of the tip member. The first wire extends to the proximal end of the distal end portion of the coil spring and is held in place by a lump of solder which extends between adjacent coil turns of the coil spring guide at the proximal end of the distal end portion of the coil spring guide. The other or second wire extends all the way back to the proximal end of the coil spring guide.
In the use of the coil spring guide disclosed in the Cook U.S. Pat. No. 3,521,620, retraction of the wire on one side of the cylindrical envelope will cause the tip to be pulled rearwardly. However, the first wire on the other side of the cylindrical envelope is prevented from moving because it is fixed at one end to the tip member and at the other end to the solder plug which engages turns of the coil spring. This results in bending of the first wire which is under compression and resulting bending of the distal end portion or tip of the coil spring guide.
The Jeckel et al. U.S. Pat. No. 3,528,406 discloses an unsheathed flexible spring guide tip which has two core wires one of which is thinner than the other with the thinner wire extending to and being fixed to a plug at the distal end of the tip and both the thinner wire and thicker wire being fixed to the proximal end of the spring guide and with the thicker wire extending only to the beginning of the tip so that the tip is more flexible.
In another embodiment disclosed in the Jeckel et al. U.S. Pat. No. 3,528,406, the core wire has a reduced-in-diameter section at the tip thereof which extends from the thicker portion of the core wire to the back side of the end plug and is fixed thereto.
The Cook U.S. Pat. No. 3,547,103 discloses an unsheathed coil spring guide which has a predetermined "J" set in the tip portion thereof. A core wire extends within the coil spring to the center back side of the tip member and is fixed thereto. The "J" shape of the tip portion is straightened by stretching the proximal end of the coil spring guide thereby compressing the tip portion of the coil spring guide to bring it from a curved "J" shape to a straight position.
The Tate U.S. Pat. No. 3,841,308 discloses a distally valved catheter device which includes a coil spring having the turns of the coil spring at the distal end thereof spaced apart. A coating or sheath covers the coil spring and the portion of the coating at the tip has ports therein. A closure or tip member is located at the distal end of the coil spring and has a stylet connected to the back side thereof and extending within the coil spring. Movement of the stylet will cause compression of the coil spring at the distal tip thereby to crumple the coating at the tip in an accordian-like fashion to close the ports therein.
The Fleischhaker et al. U.S. Pat. No. 3,973,556 discloses a smoothened coil spring wire guide where a coil spring wire is coated with a plastic coating such as Teflon.TM. and then material is removed to provide a smoothened surface partially defined by the machine Teflon.TM. and partially defined by the machined outer side surfaces of the turns of the coil spring wire. In this way, when the coil spring is bent, the Teflon.TM. or other plastic material provides a seal between the expanded turns so that the body fluids and material cannot enter into the lumen or cylindrical envelope defined by the coil spring wire guide. There is no disclosure in this patent as to how the coil spring wire guide would be bent.
As will be described in greater detail hereinafter, the coil spring guide with deflectable tip of the present invention differs from the previously proposed coil spring guides by providing for the eccentric connection of a reduced-in-diameter distal end portion of a core wire to a head or plug member at the distal end of a coil spring guide where the turns of the coil spring at the distal end portion thereof are spaced apart and wherein the coil spring guide and head or plug member are encased within a sheath. In this construction of a coil spring guide, the eccentric mounting of a reduced-in-diameter end portion of a core wire, namely connecting the distal end thereof to the back side of the head member adjacent one side thereof will result in deflection of the distal end portion of the coil spring guide outwardly from that lateral side of the head member to which the core wire is attached when the core wire is moved rearwardly.